The problem with brawler isn't at the 7+ level, I actually think there is some cool stuff there. Its at 3rd....brawler realistically gets nothing that a fighter with a couple of weapons doesn't already have....but then that fighter actually gets something from their subclass. That's the area that needs adjustment.I think people are seriously underestimating Brawler. Probably an extension of people underestimating weapon masteries. The subclass could do with a bit more polish, working out the places where its features interact unfavorably with each other, but overall I think it looks really strong.
But yeah at the higher levels when you can use 2 masteries at the same time and some other things, ok yeah that's cool and gives it a power scale all its own.